Interpretive Summary: Guar gum is the principal gum used as a sticking agent (tackifier) for hydraulically-applied mulch (hydromulch) used in erosion control, and as a clumping agent for biodegradable cat litters. Guar is currently being heavily utilized in hydraulic fracturing to release petroleum, natural gas, or other substances for extraction, which has led to unprecedented price increases, creating a pressing need for cheaper alternatives. We examined several lower-cost alternatives to guar for these applications. These included seedmeals from the oilseed crops camelina and lesquerella which contain gums; the commercial gums xanthan and plantago; pectin, lignin and methyl cellulose, which are not gums but have been used as adhesives; corn starch; and two corn starch-lipid complexes which we synthesized, one with normal corn starch and the other with high levels of amylose. Plantago and xanthan gums, lignin, the camelina and lesquerella seedmeals, and the high-amylose starch-lipid complexes were as effective in resistance to simulated rainfall as guar as when used as hydromulch tackifiers. For cat litter clumping ability, plantago and xanthan gums and methyl cellulose were equally as effective as guar gum, while pectin and the normal starch-lipid complex had acceptable clumping. At a higher usage rate both the lesquerella seedmeal and the high amylose starch-lipid complex had acceptable clumping but not at the lower rate. These results demonstrate alternative ingredients available to producers have the ability to maintain product characteristics and contribute to lower prices for consumers.

Technical Abstract:
Guar gum is currently the principal gum used as a tackifier for hydromulch used in erosion control, and as a clumping agent in biodegradable cat litters. Due to recent severe price increases for guar gum, cheaper alternatives are being investigated. We examined several alternatives, including xanthan gum, plantago gum, methyl cellulose, pectin, lignin, camelina (Camelina sativa L. Crantz) and lesquerella [Lesquerella fendleri (A. Gray) S. Wats.] seedmeals (which both contain polysaccharide gums), waxy corn starch (which lacks amylose), and both high amylose-(70% apparent amylose content) and normal (25% apparent amylose content) corn starch-sodium palmitate inclusion complexes produced by steam jet cooking. Plantago and xanthan gums, lignin-CaCl2, camelina and lesquerella seedmeals, and the high amylose starch-sodium palmitate inclusion complex were as effective in resistance to simulated rainfall as guar as when used as hydromulch tackifiers at a standard application rate. Methyl cellulose, pectin, waxy starch and the normal corn starch-sodium palmitate inclusion complex had lower rainfall resistance than guar. For cat litter clumping ability, plantago and xanthan gums and methyl cellulose were equal to guar gum at the 2% rate. Pectin and the normal starch-sodium palmitate inclusion complex had acceptable levels of clumping at this rate. Lesquerella seedmeal and the high amylose starch-sodium palmitate inclusion complex had acceptable clumping only at the higher (6%) rate tested but not at the 2% rate. Neither camelina seedmeal nor waxy starch had acceptable clumping values at either rate. These results indicate that several of these materials are potential alternatives to guar as a tackifier for hydromulch and in clumping cat litters, particularly if material costs are significantly lower.